L604C Equivalent & Substitute Parts

Part Overview

The L604C is an 8 NPN Darlington transistor array manufactured by STMicroelectronics, rated for 90V collector-emitter breakdown voltage and 400mA maximum collector current in an 18-DIP package configuration. This component is classified as obsolete, necessitating identification of active substitute parts for new designs and ongoing production requirements. The obsolete status of the L604C makes sourcing of equivalent active alternatives essential for system continuity and long-term component availability.

Substiute Parts

L604C

STMicroelectronicsIn Stock: 1173L604C Datasheet

Current PartRFQ

ULN2804A

STMicroelectronicsIn Stock: 36407ULN2804A Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the L604C is determined by the following critical parameters:

Functional Equivalence Criteria:

• Transistor configuration: 8 NPN Darlington array
• Package type: 18-DIP through-hole form factor
• Electrical ratings: Collector-emitter breakdown voltage, maximum collector current, saturation voltage characteristics
• Thermal performance: Operating temperature range and maximum power dissipation
• Compliance: RoHS3 compliance and MSL rating

The ULN2804A qualifies as a substitute based on matching transistor array configuration (8 NPN Darlington), identical package format (18-DIP), and compatible electrical operating parameters within the specified ranges. The ULN2804A is an active product with superior inventory availability and current manufacturing status.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: ULN2804A

The ULN2804A is the appropriate substitute for the obsolete L604C based on the following factors:

1. Product Status: The ULN2804A is an active product with current manufacturing support from STMicroelectronics, ensuring long-term availability and supply chain continuity.

2. Compliance Alignment: Both components maintain ROHS3 compliance and identical MSL ratings, satisfying regulatory and environmental requirements without modification to assembly or storage procedures.

3. Electrical Compatibility: The ULN2804A accommodates all L604C operating parameters within its rated specifications for applications operating at collector-emitter voltages of 50V or below and collector currents up to 400mA.

4. Package Compatibility: The 18-DIP package format is identical, enabling direct board-level substitution without PCB redesign.

Application Constraints: The ULN2804A is suitable for replacement in applications where the collector-emitter breakdown voltage requirement does not exceed 50V. Applications requiring the full 90V rating of the L604C require alternative component selection outside the provided substitute list.

Frequently Asked Questions (FAQ)

Q: Can the ULN2804A directly replace the L604C in all applications?

A: The ULN2804A is a direct substitute for applications operating at collector-emitter voltages of 50V or below. Applications requiring the full 90V breakdown voltage rating of the L604C cannot use the ULN2804A as a substitute.

Q: Are there package compatibility issues between L604C and ULN2804A?

A: No. Both components use the 18-DIP package format with identical pin spacing (0.300", 7.62mm). Direct board-level substitution is possible without PCB modification.

Q: What is the impact of the lower saturation voltage in the ULN2804A?

A: The ULN2804A exhibits a lower saturation voltage (1.6V) compared to the L604C (2.0V). This results in reduced power dissipation and improved switching efficiency in saturation mode, representing a performance improvement for most applications.

Q: Are there temperature range differences between these components?

A: The L604C operates from -25°C to 150°C, while the ULN2804A operates from -20°C to 150°C. The ULN2804A does not extend to -25°C minimum temperature. Applications requiring operation below -20°C require verification of alternative solutions.

Q: Do both components meet current regulatory requirements?

A: Yes. Both the L604C and ULN2804A are ROHS3 compliant with MSL rating of 1 (Unlimited), satisfying current environmental and regulatory standards without additional qualification.

Q: What is the inventory status difference between these parts?

A: The L604C has 1,127 pieces in stock with obsolete status. The ULN2804A has 36,340 pieces in stock with active product status, providing superior long-term availability and supply security.